Juventus win on Conte's return, Inter go second
Stephan Lichtsteiner scored Juve's winner early in the second half of a game in which both teams struggled on a difficult pitch that cut up badly following a hailstorm at half-time.
Inter's Colombian Fredy Guarin scored the first goal and set up a second for Diego Milito as they took a 2-0 halftime lead against Napoli, who had started the weekend in second.
Edinson Cavani pulled one back for the visitors early in the second half, the Uruguayan's 11th league goal of the season, and the rest of the match was an end-to-end affair in which almost every attack produced a chance.
AC Milan continued their revival with a third league win in a row, coming from behind to win 4-2 at Torino with goals from Robinho, Antonio Nocerino, Giampaolo Pazzini and Stephan El Shaaraway.
Their celebrations were dampened by an injury to their Netherlands midfielder Nigel de Jong, who ruptured an Achilles tendon and was ruled out for the rest of the season, while Robinho and Philippe Mexes were involved in a heated row on the pitch at the end.
Pescara beat Genoa 2-0 in a clash of two teams stuck in the relegation zone and two goals from Gonzalo Bergessio gave Catania their first away win of the season, 3-1 at Siena.
Juve's victory, their 12th in 16 league games, took them on to 38 points, four ahead of Inter with Napoli a further point back in third place.
"The last four months have been painful," Juve coach Conte told reporters. "It's hard to be kept out of the 90 minutes after you have prepared the team with passion and enthusiasm."
Conte was initially banned for 10 months in August for failing to report a match-fixing attempt when he was coach at Siena in Serie B, but his suspension was later reduced to four months on appeal.
Palermo playmaker Fabrizio Miccoli had a first-half goal disallowed for offside before Switzerland full-back Lichtsteiner settled the match following a clever backheel by Mirko Vucinic five minutes after the restart.
The hosts, who are 17th, had Michel Morganella sent off for a second bookable offence in the 75th minute.
Guarin, one of seven South Americans in Inter's starting lineup, opened the scoring in the eighth minute at freezing San Siro when he volleyed home Antonio Cassano's corner at the far post.
Guarin also set up the second for Milito in the 39th, threading the ball into the penalty area where the Argentine held off a challenge and slipped his shot past Morgan De Santis.
Cavani pulled one back for Napoli after an astonishing scramble in the 54th minute and they had numerous chances to equalise after that with Inter's Alvaro Pereira desperately lucky not to concede an own goal.
In Turin, Milan lost midfielder Nigel de Jong in the 21st minute and Torino went ahead seven minutes later when Antonio Nocerino's dreadful backpass was intercepted by Mario Santana, who ran into the box and rounded Marco Amelia to score.
Milan's Brazil forward Robinho levelled from a tight angle five minutes before half-time and Nocerino made amends for his blunder after the break when he headed in a rebound after Jean-Francois Gillet parried the ball into his path from El Shaaraway's cross.
Pazzini scored the third, despite Torino claims he had committed a foul in the process, and El Shaaraway tapped in from close range after a mistake by Gillet for his 13th goal of the season before Rolando Bianchi headed one back for Torino.
The win saw Milan climb to seventh with 24 points.
Pescara's Slovakia midfielder Vladimir Weiss set up both their goals in the second half against Genoa, the first for Elvis Abbruscato and the second for Ante Vukusic.
Pescara moved up to 18th with 14 points, two more than their opponents who are 19th in the 20-team table.